Aljazeera

A US soldier and a civilian contractor have been killed in Afghanistan by an Afghan soldier, bringing the total number of US soldier deaths in the 11-year-old conflict to 2,000.

A US official, who asked not to be identified, told Reuters news agency on Sunday that an American soldier and a civilian contractor had been killed in the incident in eastern Afghanistan.

The attack happened at about 12:30 GMT on Saturday in the Sayd Abad district just outside a joint US-Afghan base in Wardak province, an Afghan defence ministry spokesman said on Sunday.

NATO forces would only say that it was a "suspected insider attack" and that a NATO service member and civilian contractor were killed.

Saturday's attack brings the total number of ISAF troops killed in 36 such attacks this year to 52, accounting for about 15 per cent of all coalition casualties in the war.

Al Jazeera's Bernard Smith, reporting from Kabul, quoted witnesses as saying that gunfire erupted after a dispute between International Security Assistance Force (ISAF) soldiers, who were manning the checkpoint, and an Afghan National Army patrol.

"[The NATO troops] were searching vehicles [carrying] men, women and children, and an Afghan Army patrol came along the highway [from their own checkpoint]. The Afghan patrol complained that the NATO troops were checking women and children, and it seems as a result of this confrontation a firefight broke out," he said.

"It's a particularly grim day for the American forces because that death brings to two thousand the number of troops killed here in Afghanistan in more than ten years."

So-called insider attacks are now among the biggest threats to coalition troops.